http://www.theolympicdatabase.nl/home.php?lang=EN (only data until 2008, Beijing) http://www.sports-reference.com/olympics/ http://www.bbc.com/sport/olympics/36373149
http://yourdatastories.eu/rio-2016-the-bigdata-olympics/ https://www.facebook.com/photo.php?fbid=10154471212478069&set=a.10150865658558069.439854.581833068&type=3&theater